Variable size folding machines



Nov. 26, 1957 A. R. STOBB ETAL' 2,814,434

VARIABLE SIZE FOLDING MACHINES Filed Oct. 26, 1953 s Sheets-Sheet 1 Nov. 26, 1957 A. R. STOBB ETAL VARIABLE szzr: FOLDING MACHINES 6 Sheets-Sheet 2 Filed 001.. 26. 1953 Nov. 26, 1957 A. R. STOBB TAL VARIABLE SIZE FOLDING MACHINES 6 Sheets-Sheet 3 Filed Oct. 26, 1953 Nov. 26, 1957 A. R. s'roaa ETAL VARIABLE SIZE FOLDING MACHINES 6 Sheets-Sheet 4 Filed Oct. 26. 1953 Nov. 26, 1957 A. R. s'roaa ETAL 3 VARIABLE SIZE FOLDING MACHINES Filed Oct. 26, 1953 6 Sheets-Sheet 5 Nov. 26, 1957 A. R. STOBB ETAL VARIABLE SIZE FOLDING MACHINES Filed Oct. 26. 1953 6 Sheets-Sheet 6 United States Patent 2,814,484 Patented Nov. 26, 1957 VARIABLE SIZE FOLDING MACHINES Anton R. Stobb, Racine, Wis., and William Henry Miles, Bristol, England; said Miles assignor to Strachan & Henshaw Limited, Bristol, England, a British company Application October 26, 1953, Serial No. 388,212

8 Claims. (Cl. 270-43) This invention relates to variable size folding machines, and more particularly to the cylindrical members employed in paper converting machines for the folding or otherwise handling of predetermined lengths of paper web.

In the manufacture of products from a continuous paper web it often occurs that it is necessary for the web to be delivered from one part of the machine at a different speed to that at which it has to be presented to another part of the machine. This condition applies in contin uous Web fed rotary machines for printing and folding book signatures of multi sizes. Usually, the folding cylinder is of set diameter for all sizes of book signatures, and is of sufficient diameter to accommodate the longest pull or length of web which will be used. The pull size or length of web varies according to the product to be produced, and in consequence some means must be introduced before the fol-ding mechanism to effect synchronisation of the two running speeds, that is, of the web and of the folding mechanism. It has been necessary therefore to provide suitable means between the printing unit and the folding unit to ensure that the severed portions of the web are presented to the folding cylinder at the same speed as the peripheral speed of the folding cylinder no matter at which speed the web is delivered from the printing unit.

Web speed compensating means have been provided, for the purpose described, by which the web is severed into separate lengths for the production of book signatures, after delivery from the printing unit, and each severed Web length is then accelerated so that its speed agrees with the speed at which it has to be presented to the folding cylinder so that when the web length is claimed by the folding cylinder the speeds synchronise. These known web speed compensating means apply a travelling effort to the severed web length in such a manner that the web length is pushed to the folding cylinder, the leading edge of the web length not being under positive control. The required relation between the printing and folding units can be effected by substituting in the folder a new primary cylinder of appropriate diameter, but this requires much effort and time to achieve, and it also requires a large range of cylinders of varying diameters to be provided.

The object of the present invention is to provide an improved roll, hereinafter referred to as a primary cylinder for a variable size folding paper machine, of which the circumferential speed is maintained, for all ranges of products, synchronous with the speed of the web as delivered from the printing machine, without the use of compensating means which operate during the working of the machine.

A primary cylinder for a variable size paper folding machine according to this invention is characterized in that said cylinder has a periphery provided by segmental elements, said segmental elements being adjustable radially of the cylinder axis whereby the diameter of said cylinder may be varied. When a larger diameter printing roll is used, the cylinder diameter is increased proportionately. Thus the surface speeds of the roll and the cylinder remain the same and no Web speed compensating means are required between the printing and folding units.

The variable diameter cylinder may comprise two series of segmental elements, each series comprising at least two segmental elements, the elements of the first series thereof alternating circumfercntially with the elements of the second series, the elements of the second series thereof each having their edges in the circumferential direction overlapping the adjacent edges of the elements of the first series, and all of the elements of both series being adjustable radially of the cylinder axis. Clamping devices may be provided for locking the elements in positions to which they have been adjusted radially. The elements of the first series thereof may be permanently mounted in the cylinder, whilst the elements of the second series thereof may be removably mounted in the cylinder whereby second series elements of various radii and arcuate lengths may be mounted in the cylinder.

One form of variable diameter primary cylinder according to this invention, for a variable size folding machine, is illustrated in the accompanying drawings, wherein:

Fig. l is a diagrammatic view showing the relation between the primary cylinder, a secondary folding cylinder and a rotary web severing device.

Figs. 2 and 3 are end elevations of the primary cylinder, with parts in section, and showing only the segmental elements and supporting elements immediately associated therewith, Fig. 2 showing the cylinder in its position of minimum diameter, whilst Fig. 3 shows the cylin der in an enlarged diameter position;

Fig. 4 is an end view of the primary cylinder and the rotary web severing device.

Figs. 5 and 5 continued are, together, a longitudinal section of the primary cylinder, on line V--V of Fig. 4;

Fig. 6 is a fragmentary elevation of a detail, looking in the direction of arrow VI in Fig. 5.

Fig. 7 is an elevation of part of the primary cylinder, with parts in section, looking in the direction of arrow VII in Fig. 5;

Fig. 8 is an elevation of part of the primary cylinder, with parts in section, looking in the direction of arrow Vlll in Fig.4, and

Fig. 9 is an end view of the primary cylinder, showing certain elements only, all other elements being eliminated for clearness of illustration.

The primary cylinder 11 is associated with a rotary web severing device 12, Fig. l, and with a secondary folding cylinder 13. The secondary cylinder 13 is of fixed diameter and is mounted with its axis in a fixed position in relation to the remainder of the folding machine which is not illustrated. The primary cylinder 11 is of variable diameter and is movable towards or away from the axis of the cylinder 13, to accommodate variations in the diameter of the cylinder 11, so that the adjacent portions of the peripheries of the two cylinders always are disposed in correct relation to each other. The rotary web severing cylinder 12 has a blade 14 and is adjustable so that the radial distance of the cutting edge of the blade from the axis of the device is variable so as always to retain said radius at a fixed ratio to the radius of the primary cylinder 11; in the example illustrated this ratio is 1 to 3. The web severing device is movable away from or towards the axis of the primary cylinder 11, to accommodate variations in the diameter of the cylinder 11 and radius of the blade 14, so that they always are so disposed in correct relation to each other for the severing blade 14 to co-operate with corresponding means on the cylinder 11 to sever the web 15.

The said movement of the cylinder 11 and severing device 12 may be effected by a screw threaded spindle 16 which is provided with two separate screw threads 17 and 18 of difierent pitches. The thread 17 engages a nut 19 on the bearing block 20 of the severing device 12, whilst the thread 18 engages a nut 21 on the bearing block 22 of the cylinder 11. The ratio between the pitches of the threads 17 and 18 is such that when the axis of the cylinder 11 is moved away from or towards the axis of the secondary cylinder 13, by rotating the spindle 16. to adjust the relative positions on variation of the diameter of the cylinder 11, the axis of the web severing device 12 also is moved away from or towards the axis of the cylinder 11 the correct amount to retain the blade 14 and the periphery of the cylinder 11 in their correct relationship.

Although the web 15 is referred to in this specification in the singular, it may, as in the example illustrated. comprise a collection of two or more, for example, four, ribbons 34 which are received separately from the print ing machine so that each pull of the web on to the cylinder 11 comprises four superimposed sheets cut from the Web. The web is fed from the ribbon collector 23 to the cylinder 11 at a tangent at the line of contact between the cylinder 11 and the blade 14. The ribbon collector 23 is adjustable on its frame 24 in order to retain this feed position of the web when the diameter of the cylinder 11 is varied.

The primary cylinder 11 has a shaft 25 which has mounted on it two spaced apart end discs 26, 27 which are free to move axially but keyed so as to rotate with the shaft, each disc being provided with six radial slots 28 equally spaced apart angularly.

Two series of segment support members are Provided at each end of the cylinder, the support members 29 of the first series thereof alternating around the discs 26 and 27 with the support members 30 of the second series thereof. Each support member 29 and 30 is provided with a boss which forms a slide 31 to engage in a slot 28 so that the support member may be moved radially of the axis of the shaft 25.

The cylinder 11 also comprises two series of segmental elements. each of which extends along the cylinder between the two discs 26, 27, the segmental elements 32 of the first series thereof alternating around the cylinder with the segmental elements 33 of the second series. Each first segmental element 32 is rigidly connected at each end thereof to a segment support member 29 on each disc 26, 27; similarly, each second segmental element 33 is rigidly secured at each end thereof to a segment support member 30 on each disc 26, 27. The first segmental elements 32 are secured to their support members 29 in a substantially permanent manner, the term permanent in this connection indicating that the segmental element is not normally removed from the support member except for renewal or maintenance purposes. The second segmental elements 33 are secured to their support members 30 in such manner, for example, by screw studs, as to be easily removable therefrom.

The circumferentially directed edges 35 of the second segmental elements 33 overlap the adjacent edges 36 of the first segmental elements 32 (Figs. 2 and 3); the overlapping portions of the second segmental elements 33 have planar inwardly directed surfaces 37 which lie in facial contact with outwardly directed planar surfaces 38 on the peripheries of the first segmental elements 32 when the cylinder is adjusted to the minimum diameter with a particular size set of second segmental elements 33 (Fig. 2); the arrangement is such that no matter to What extent the segmental elements are adjusted radially, the second segmental elements 33 will always overlap the first segmental elements 32 to some extent (Fig. 3), and thereby a substantially continuous periphery is provided for the cylinder.

There may be any plural number of elements in each series of segmental elements, provided there always are the same number in each series, but it has been found convenient to have three elements in each series, that is, six elements in all. This arrangement makes it very convenient for the primary cylinder to accommodate three pulls of sheets in succession around the cylinder, the peripheral length of the cylinder being adjusted, by radial adjustment of the elements, until said peripheral length is equal to three pulls of sheets. The cylinder is provided with grippers adapted to engage the leading edge of a pull of sheets, web severing elements adapted to co-operate with the rotary severing blade 14 to cut the web immediately in front of the grippers so as to provide a trailing edge to one pull of sheets and a leading edge to the next pull, and tucker blades adapted to press a pull of sheets across a line substantially medially between its leading and trailing edges. outwardly from the primary cylinder so as to be claimed by the gripper elements in the secondary folding cylinder 13.

There is a complete set of bottom and top grippers 39 and 40, respectively, and a web severing element 41 in each first segmental element 32. and a tucker blade 42 associated with each second segmental element 33. As there is only one severing blade 14 in the severing device 12, which has to co-operate with all three severing elements 41 on the cylinder 11 in turn, the web severing device 12 will rotate three times to each revolution of the primary cylinder 11. When the primary cylinder 11 is adjusted, in the manner hereinafter described, for its peripheral length to equal three pulls of sheets, the radial distance of the cutting edge of the blade 14 from the axis of the device 12 also is adjusted so that the blade always will co-operate exactly with the severing elements 41.

The peripheral length of the primary cylinder 11 is varied by moving all of the segment support members 29, 30 simultaneously outwardly or inwardly radially on the end discs 26, 27. One set of second segmental elements 33 have a sufiicient peripheral length to provide for a radial movement of each element of, for example. half an inch, that is a diametral increase of one inch in the cylinder. If it is desired to increase the diameter of the cylinder 11 more than, for example, one inch, then a larger set of second segmental elements 33 are sub stituted on the support members 30.

Radial movement of the support members 29 and 30, and the segmental elements 32 and 33, relative to the end discs 26, 27 is effected in the following manner.

A sleeve 43 is mounted, relatively rotatable and axially movable, on the shaft 25 between the end discs 26, 27, and this sleeve carries at each end thereof a spiral threaded annulus or scroll 44. Each segment support member 29, 30 carries a spiral-threaded segment or scroll dog 45. All the scroll dogs 45 on the members 29, 30 at one end disc 26 are in engagement with the scroll 44 at one end of the sleeve 43, and similarly all the scroll dogs 45 on the members 29, 30 at the other end disc 27 are in engagement with the other scroll 44. When the sleeve 43 and scrolls 44 are rotated relatively to the shaft 25, the spiral arrangement of the (o-operating threads on the scrolls 44 and scroll dogs 45 will cause the support members 29, 30 to move radially with re spect to the shaft 25 and end discs 26. 27. Rotation of the sleeve 43 relative to the shaft 25 is effected by a spindle 46 which is mounted, rotatably, in the end disc 26 and is provided at its inner end with a spur wheel 47 which engages a toothed gear 48 on one of the scrolls 44; the outer end 49 of the spindle 46 is adapted for a key to be applied thereto so that the spindle can be rotated manually.

When radial adjustment of the segmental elements 32, 33 and their support members 29, 30 has been effected. they are locked in position, so that they cannot move further radially, by locking the sleeve 43 and scrolls 44 against rotation relative to the shaft 25 and end discs The end discs 26, 27 are axially movable on the shaft 25, by means of keys 50, and the end disc 27 abuts against a collar 51 on the shaft 25. The end disc 26 is provided externally with an axial boss 52. A locking ring 53 is rotatably mounted on the shaft 25, and abuts another collar 54 on the shaft 25. The ring 53 is in screw-threaded engagement with the boss 52 at 55, and is provided with worm teeth '6 which are engaged by a worm, not shown, which is rotated manually to effect rotation of the ring 53. When the ring 53 is rotated, the screw-threaded engagement 55 between the ring and the disc 26, together with the axial abutment oi the ring with the collar 54, causes the disc 26 to be moved axially along the shaft 25 towards the disc 27; as axial movement of the disc 2.7 is limited by the collar 51, the whole assembly of sleeve 43, scrolls 44, scroll dogs 45, segment support members 29, 30, and end discs 26, 27 are locked frictionally to each other. In order to facilitate this frictional locking engagement, the screw threads on the scrolls 44 and scroll dogs 45 are square so as to provide substantial facial abutment surfaces between tops or outer ends of the teeth on the scrolls and bottoms or roots of the teeth on the scroll dogs. Furthermore, the teeth on the scroll dogs 45 are bounded at either side, in a circumferential direction, with planar surfaces 57, Fig. 6, in the plane of the roots of the said teeth, which planar surfaces provide additional frictional abutment surfaces for engagement with the tops of the teeth on the scrolls 44.

The periphery of each first segmental element 32 is arcuate with a radius equal to the smallest radius to which the said element may be adjusted relative to the shaft 25, whilst the periphery of each second segmental element 33 also is arcuate with a radius equal to the smallest radius to which said element may be adjusted. The cylinder 11 will only be truly circular when the first segmental elements and the smallest set of second segmental elements are in their position of minimum radius. The arcuate lengths of the second segmental elements 33 are such that said elements provide the major portion of the periphery of the cylinder, the exposed arcuate faces of the first segmental elements 32 providing only a small part of the cylinder periphery. The radial adjustment of a certain size of second segmental elements is small, and below or above the radial adjustment limits of said certain size a new set of elements, of smaller or larger size, is mounted on the second support elements. The curvature of the arcuate faces of the first segmental elements conforms to the cylinder diameter at only one setting, the smallest, of the latter, but the exposed portions of said faces of the first segmental elements are so narrow (being overlapped by the second segmental elements), and the range of radial adjustment of second segmental elements of a particular curvature is so small, that any deviation of the cylinder from true circularity is not to great as to interfere with the required working of the cylinder, that is, to operate upon a predetermined length of web.

As indicated hereinbefore, there is a set of bottom and top grippers 39 and 40 at each first segmental element 32. When the cylinder 11 is not collecting, the bottom grippers 39 are arranged to operate without gripping, whilst the top grippers 40 operate to grip, by descending on to the bottom grippers 39, the leading edge of each consecutive pull of sheets. When the cylinder is collecting, the bottom grippers 39 grip the leading edge of alternate pulls of sheets. In. this specification, reference to collecting" means that two pulls of sheets are collected by the cylinder 11 to form a single signature before they are claimed by the secondary folding cylinder 13. Alternate pulls are printed similarly, the first pull is taken by the bottom grippers 39 at a position on the cylinder 11, taken one complete revolution of the cylinder without being claimed by the cylinder 13, and then a second, differently printed, pull is taken by the top grippers 40, at the same position, on top of the first pull and on top of the grippers 39, and both superimposed pulls are taken part of the way round the cylinder 11 before being claimed, as one signature, by the cylinder 13. The arrangement of three sets of grippers 39, 40 on the cylinfi der 11, at equally spaced angular intervals, ensures that a first pull is collected by the grippers at a single position only once in every two revolutions of the cylinder 11, a second pull being collected at the same position in the alternate revolution.

Similarly. nonrcollecting in this specification means that only one pull of sheets is taken by the cylinder 11 and transferred as a complete signature to the secondary folding cylinder 13. A pull of sheets is taken by the top grippers 40 at each revolution of the cylinder 11, and although the grippers 39 will also operate, they will close before the gripping position, the pull of sheets being gripped between the grippers 39 and 40 each revolution.

The operation of the grippers can be seen from Figs. 5 and 7. In each set of grippers at a position on the cylinder 11 there is a bottom gripper 39 and a top gripper 40 towards each end of the cylinder. Both grippers 39 and 40 at an end are rotatably mounted, separately, on a spindle 58 whose axis is at right angles to the axis of the shaft 25, the two grippers being disposed side by side and cranked to that the actual operative end 59 of the top gripper 40 is superimposed on the operative end 60 of the bottom gripper 39. The spindle 58 is mounted in a carrier 61 which is mounted to slide in the segment support member 29 in a direction parallel to the shaft 25. The two carriers 61, one at each end of the cylinder, are connected together by a shaft 62 which has a righthand thread for engagement with one carrier, and a left-hand thread for engagement with the other carrier. A bevel gear wheel 63 (Fig. 5) secured to the shaft 62 is in engagement with a bevel gear wheel 64 on a spindle 65 which is rotatably mounted in a fixed carrier 66 secured to the support member 29, the outer end 67 of the spindle 65 being adapted for a key to be applied thereto so that the spindle may be rotated manually for setting. When the spindle 65 is rotated, the two carriers 61, together with the grippers 39, 40 thereon, are moved towards or away from each other so that the spacing between. the grippers at one end of the cylinder from the grippers at the other end may be adjusted to suit the width of sheets which are to be operated upon. A portion 68 of each carrier 61 projects through a slot 69 (through which the grippers also project) in the segmental element 32 so as to lie flush with the surface of said element and cooperate With the grippers 39, 40 to grip a pull of sheets.

Two shafts 70, 71 extend between the two support members 29 for a segmental element 32 and are rotatably mounted therein. The two shafts 70, 71 also pass, rotatably and axially slidable, through both gripper carriers 61. The shaft 70 carries at each end a bevel gear member 72, which is slidably keyed thereto in a keyway 73 so as to be rotatable with the shaft but slidable longitudinally thereon, the gear member being mounted within the carrier 61 and being in engagement with a bevel gear member 74 secured to the bottom gripper 39. When the shaft 70 is moved angularly about its axis, the two bottom grippers 39 also are moved angularly on the spindles 58 so that they can be raised from and returned to the gripping position. Similarly, the shaft 71 carries a slidable gear member 75 at each end on a keyway 76. the gear members being disposed in the carriers 61 and being in engagement with gear members 77 secured to the top grippers 40 so that angular movement of the shaft 71 will cause the grippers 40 to rise or fall so as to release or grip sheets.

The shaft 70 carries a gear wheel 78, keyed thereto, which meshes with another gear wheel 79 on a spindle 80, the latter spindle carrying a crank 81 on the outer end of which is a crank pin 82, the spindle 80 being rotatably mounted in the segment support member 29 at one end of the cylinder. Similarly, the shaft 71 carries a gear wheel 83 keyed thereto, which meshes with another gear wheel 84 on a spindle 85 which in turn carries a crank 86 on the outer of which is a crank pin 87, the spindle 85 being rotatably mounted in the segment support member 29 at the other end of the cylinder.

The crank pin 82 is engaged by a slot 88 in the free end of a lever 89 (Figs. 4, and 9) which is pivotally mounted at 90 on the end disc 27 and which carries a cam follower 91 which co-operates with a cam track 92. The cam track 92 is rigidly mounted in a cam carrier 93 which is rotatable relative to the shaft 25 and has an internal toothed gear 94. An external toothed gear wheel 95 is mounted rigidly on a carrier 96 which also is rotatable relative to the shaft 25. The two gears 94 and 95 are interconnected by planet wheels 9'7 which are rotatably mounted on pins 98 secured to the end disc 27. Either the cam carrier 93 or the gear wheel carrier 96 can be rigidly secured to the frame 99 of the folding machine by a dog 100 which is carried on a shaft 101 which is rotated by a cranked handle 102, the dog 100 engaging one of the co-operative recesses 103 or 104 to secure the cam carrier 93 or the gear carrier 96, respectively, to the frame, the cranked handle 102 being secured to the frame in the selected position by a springpressed stud 105 engaging in either of recesses 106 or 107.

When the cam carrier 93 is locked to the frame 99, the cam track 92 is stationary and the bottom grippers 39 are actuated to open and close once during every revolution of the cylinder 11, the open position being determined by the radially outermost portion 108 of the cam track; this is the non-collecting position.

When the gear carrier 96 is secured to the frame 99, the cam carrier 93 rotates around the shaft 25 and gear carrier 96 at a speed ratio to the cylinder of three to two, in the same direction, that is, the cam track completes one revolution whilst the cylinder makes two-thirds of one revolution; consequently, if the cylinder rotates in the direction of the arrow, Fig. 4, then the grippers 39 at each of the three positions on the cylinder, that is, positions A. B and C, will be actuated to open in succession in that order, and therefore the grippers 39 at any one position will be opened once in every two revolutions of the cylinder. This is the collecting condition.

The crank pin 87 is operated by a similar assembly at the end disc 26, namely, a slot 109 in a lever 11!] which is pivoted at H1 on the disc 26 and which carries a cam follower 112 which engages a cam track 113 mounted in a cam carrier 114; however, the cam carrier 114 is always rigidly secured to the frame 99 so that the grippers 40 are opened once during each revolution of the cylinder, whether the cylinder is set for non-collecting or collectirlg.

The arrangement of the levers 89 and 110, with the slots 88 and 109, is such that in the closed position of the grippers 39 and 40 the said slots and the cranks 81 and 86 are radial of the cylinder, and are aligned, so that outward or inward radial adjustment of the segmental elements 32, carrying the grippers, may be effected whilst retaining the crank pins 82 and 87 in correct positional relationship with said slots throughout all such adjustments.

The web severing element 41 in each segmental element 32 comprises a slot (Fig. 1) which is slightly in advance, in the direction of rotation of the cylinder 11, of the grippers so that the web is severed slightly in advance of the gripping position.

The signature tucker means comprises a blade 42 approximately at the centre of each segment support member 30 and adapted to be projected through a slot 115 (Fig. 5) in the segmental element 33. The blade 42 is mounted on a rocker frame 116 (Fig. 8) which is adjustably secured to a spindle 117 by studs 118, the spindle 117 being rotatably mounted in bearings in the two support members 30 for a segmental element 33. A crank 119 is mounted on a shaft 120, which is rotatably mounted in the support member 30 at one end of the element 33, a gear member 121 on the shaft meshing with a gear member 122 on the spindle 117. The crank 119 carries a cam follower 123 on its outer end and said cam follower is adapted to engage a fixed cam 124 on the machine frame 99 each time the cylinder rotates in such manner that when the cam follower 123 is pressed inwardly of the cylinder by the cam 124 the blade 42 is pressed outwardly of the cylinder through the slot 115 whereby to press sheets which lie around the cylinder and across said slot into gripper elements 125 on the secondary folding cylinder 13. Simultaneously with the sheets being claimed by the cylinder 13 they are released by the grippers 39 and 40. Normally, the crank 119 is pressed outwardly by a spring 126, and its outward movement is limited by a stop 127.

The secondary folding cylinder 13 is provided with two diametrically opposed positions for gripper elements 125. The cylinder 13 is adapted to rotate once to each twothirds of a revolution of the cylinder 11 so that a claiming jaw position registers with every slot 115 during every revolution of the cylinder 11. If the cylinder 11 is set for non-collecting, the claiming jaws 125 are mounted in both positions on the cylinder 13 so that sheets are claimed from the cylinder 11 every time a slot 115 and tucker blade 42 passes the cylinder 13. If, however, the cylinder 11 is set for collecting, the claiming jaws 125 are mounted at one position only on the cylinder 13; thereby, although the tucker blades 42 will press out the sheets from the surface of the cylinder 11 every time they pass the cylinder 13, the sheets only at alternate tucker blades will be claimed by the cylinder 13. This arrangement enables alternate claiming of the pulls of web to be effected without having to incorporate selecting mechanism in the cylinder 13 to effect alternate tucking. The position of the cam followers 123 in relation to the fixed cam 124 is substantially constant at all diameters of the cylinder 11, the line of contact between the cylinders 11 and 13 being constant and the fixed cam 124 being disposed near to said line of contact.

Although, with some diameters of the primary cylinder 11, there may be a difference in surface speed between the said cylinder and the secondary folding cylin der 13, it has been found that this difference creates no difficulty, and that careful setting of the tucker blades 42 and the gripper elements 125 will enable satisfactory transfer of a signature from the primary cylinder 11 to the secondary cylinder 13 to be effected despite the different speeds of the parts.

What we claim and desire to secure by Letters Patent 1. A primary cylinder for a variable size paper folding machine, said cylinder having its periphery provided by two series of segmental elements, each series comprising at least two segmental elements, the elements of the first series thereof alternating circumferentially with the elements of the second series, said segmental elements being adjustable radially of the cylinder axis whereby the diameter of said cylinder may be varied, means for mounting said elements for enabling said radial adjustment of the said elements to be effected, said means comprising a shaft disposed axially of the cylinder, two end discs mounted on said shaft for rotation therewith, said end discs each being provided with radial slots equiangularly spaced therearound, the number of slots in each end disc corresponding to the total number of segmental elements in both series thereof, and a slide element mounted in each said slot and adapted to slide therein radially of the shaft axis, each said segmental element being secured at opposite ends to a said slide element on each said end disc.

2. A primary cylinder according to claim 1 wherein the elements of said second series thereof each have their edges in the circumferential direction overlapping the adjacent edges of the elements of said first series thereof.

3. A primary cylinder according to claim 1, wherein the elements of the first series thereof are permanently mounted in the cylinder, and the elements of the second series thereof are removably mounted in the cylinder whereby second series elements of various radii and arcuate lengths may be mounted in the cylinder.

4. A primary cylinder according to claim 1 wherein two scrolls having a spiral screw thread thereon are rotatably mounted on said shaft and are connected together for synchronous rotation, scroll dogs are mounted on each said slide element, said scroll dogs being provided with segments of spiral screw threads, the screw threads on the scroll dogs and the scrolls being in co-operative coaction whereby when the scrolls are rotated on said shaft the slide elements are caused to move radially of the shaft.

5. A primary cylinder according to claim 4 wherein said end discs and scrolls are movable axially on the said shaft, fixed abutments on the shaft are provided outwardly of said end discs, and means are provided to move said end discs and said scrolls between said abutments and axially of the shaft whereby the said end discs and scrolls can be so moved towards one abutment as to be clamped frictionally to each other to prevent relative rotation.

6. A primary cylinder according to claim 5 wherein the means for effecting axial movement of the end discs and the scrolls axially of the shaft between said abutments comprises a screw-thread device between one said abutment and a said end disc whereby said end disc may be moved axially relatively to said abutment.

7. A primary cylinder according to claim 1 wherein sheet gripping devices are mounted on the segmental elements of the first series thereof. lever means are pivotally provided on the end discs to effect angular movement of said sheet gripping devices, a cam track is provided on a supporting frame for the cylinder whereby there is relative rotation between the earn track and cylinder, a cam follower is provided on said lever means in operative en gagement with said cam track, and the operative engagement between said lever means and said sheet gripping device is efiected by means comprising a crank on a spindle on which the gripping devices are mounted, a crack pin on said crank, and a slot in said lever, the said crank pin and said slot being in operative engagement with each other, the said slot and the said crank being disposed radially of the cylinder shaft axis when the gripping devices are in the sheet gripping position.

8. A primary cylinder according to claim 1 wherein sheet tucker means, for cooperation with claiming means on a secondary folding cylinder of the folding machine, are mounted on a spindle in the segmental elements of the first series thereof, a crank having a crank pin thereon is mounted on said spindle, and a cam is mounted in a fixed position on a supporting frame for the primary cylinder whereby there is operative engagement between said cam and said crank pin to actuate said tucker means on each revolution of the primary cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 1,001,445 Richardson Aug. 22, 1911 1,001,912 Watson Aug. 29, 1911 1,428,952 Fuhr Sept. 12, 1922 1,976,853 Lundquist et al Oct. 16, 1934 2,583,889 Schoonenberg Jan. 29, 1952 

